Radius Definition and 1000 Threads

Homework Statement Find where θ is the biggest (largest) I'll have the picture of the problem included below (pic:1) Homework Equations (x-q)2+(y+5/2)2=r2 answer x= 2 The Attempt at a Solution Hi, so my prefesor gave me this problem and told me to try to solve it. We already did this problem...

Hello all, I am trying to remember (I did it in Uni) how to calculate the effective mean radius of an annulus that contains a pattern of holes on a PCD. Consider the following image (pinched from: https://www.solenoid-valves.com/ ): If one was to vary the value of PCD, then the effective...

In linear accelerators that use a disk loaded structure (traveling wave), how would you calculate the iris(disk hole) radius, cavity radius, and disk thickness according to the wavelength

Homework Statement i was told that the hydraulic diameter = 4Ac / p , while the hydraulic radius = Ac / p , where Ac = cross sectional area , and p = wetted perimeter of the pipe , why shouldn't the hydraulic radius = 2Ac / p ? because as well all know , diameter = 2 Radius , so hydraulic...

which has different radiuses at both end. Its actually two pipes merging after the entrance going straight and somewhere close to middle of the pipe it's bent 90°. So for simple pipes it's =4*Q π*r^3 But what for the pipe I...

Homework Statement A mettalic ball is dangling from a light thread connected to an object that is floating on water the objects length is 6 cm and its area is 12 cm^2 and its density is 0.30g/cm^3 if the floating part of the object is 4 cm what's the radius of the ball (the balls density is...

Homework Statement We can make a rough estimate of how much the envelope of a red giant should expand as a result of the contraction of its core based on conservation of energy. We will consider a star of mass M and initial radius R, with a core of mass Mc and radius Rc. We will focus on the...

Homework Statement The County Fair Swing carries the mass of riders and chairs in a circular path in a horizontal plane while suspended by cables or chains. Let's assume that: Each chair with riders is supported by a single cable The tension in the cable equals 2 x the total weight riders...

My teacher was not too clear about this and from what I've gathered is if you're given two elements this is how you would figure out which one has a larger atomic radius or ionization energy, but I'm not sure if it's accurate Radius: Whichever one is in a lower period (more energy levels) has a...

Hi there, I have a question regarding the life cycle of a star. I know that when entering the red giant phase of a star's life, its radius/overall size will increase dramatically, but I was wondering if there's a basic way to determine the factor it will grow by during this process. I've seen...

Homework Statement A force field in 2-d F~ = −kr(rˆ) with U(r) = k(r^2)/2 acts on a particle of mass m. The particle is now in a non-circular orbit. In terms of the particle’s angular momentum L and energy E, d) What is its closest approach to the origin? e) What is its furthest distance from...

Ok, so here's the deal. I'm working on something that I SHOULD know the equations for after 5 years of school and a degree in mechanical engineering, but then again I can't remember why I walked into a room most times. So if ya'll could give me some guidance and at least a starting point I...

Hi everyone, i hope this is the right place to post this. Anyway, I'm creating a game, and I'm trying to calculate and project future car movement path based on steering angle of the wheels. By using equation: r = wheelbase / sin(steeringAngle) I'm able to calculate turning radius. But the...

Hi All, Having difficultly figuring out where I've gone wrong with this problem. Any guidance gratefully received. 1. Homework Statement A 4.76 keV electron (an electron that has a kinetic energy equal to 4.76 keV) moves in a circular orbit that is perpendicular to a magnetic field of 0.392...

Homework Statement Assuming that the average surface brightness within the effective radius is 19 mag/arcsec2, use the definition of the effective radius to estimate what the effective radius in kpc would be for NGC 4216 if it was an elliptical galaxy. Homework Equations All the logs are base...

I was doing some calculations using the escape velocities from Earth, Moon and Mars. Then by chance I calculated the velocities attained when an object was "dropped" from a height of the radius on each of these bodies, assuming the acceleration due to gravity remained constant during the fall...

I'm doing a homework problem where it asks to calculate the diameter of a hydrogen atom with n=600. I used the equation $$r=\frac{n^2a_0}{Z}$$ where $$a_0=0.529e^{-10}m$$. Solving for r yields: $$r=\frac{(600^2)(0.529e^{-10}m)}{1}=1.90e^{-5}m$$ Multiplying by 2 to get the diameter yields...

Hello, I have a question about the chord length of rotor blades from wind turbines. I do not really understand what the difference is to the radius of a wind turbine. I can not find a real explanation, but it seems to be very important. I know that the formula of the chord length depends on...

I would love someone to verify the answer for equation 8 in this paper (bottom of page 263) http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2028.2002.00368.x/epdf For the sake of clarity here is the equation is LaTeX which you can render at the following link \frac{QC + Q\lambda \sigma -...

Is this the proper formula for calculating the Schwarzschild radius of a black hole? rs = 2GM / c2 If it is not, or if anyone has one that might work better, could you refer it to me?

Hi - Can anyone help me out with a question. The answer seems obvious, but maybe so obvious that I'm jumping to wrong conclusions! Just been reading Guy Martin's book "When your dead, your dead" (good read by the way) and one of his stories is about breaking the world speed record for a wall of...

Radius of convergence of $\displaystyle \sum_{j=0}^{\infty} \frac{z^{2j}}{2^j}$. If I let $z^2 = x$ I get a series whose radius of convergence is $2$ (by the ratio test). How do I get from this that the original series has a radius of convergence equal to $\sqrt{2}$?

Ok so i know the equation for the volume of a cylinder and the equation for calculating the radius. But when calculating the radius does the volume need to be converted into cubic inches or can it stay as imperial fluid ounces. Thanks

I wish to solve the inverse geodesic problem numerically using http://geographiclib.sourceforge.net/html/classGeographicLib_1_1Geodesic.html#a455300c36e6caa70968115416e1573a4, and to finish off I need to specify the "equatorial radius". I am not too familiar with this, and do not see immediately...

Homework Statement A solid sphere is rolling without slipping on rough ground with an angular velocity w and linear velocity v. It collides elastically with an another identical sphere at rest. Radius of each sphere is R and mass m. What is the linear velocity of the first sphere after it...

I have a question regarding the exact formulation of the mechanism of Inflation. In thehttp://www.damtp.cam.ac.uk/user/db275/Cosmology/Lectures.pdf he uses ##\frac{d}{dt} \frac{1}{aH} < 0## as an definition of inflation. I see that it yields ## \ddot a > 0##, but my confusion lies in the...

Homework Statement x(t) = 6cos(t)−cos(6t) y(t) = 6sin(t)−sin(6t) 0 <= t <= 2*pi I need to find the area cm2 with Th Green. I need to find the radius and the center coordinate Homework EquationsThe Attempt at a Solution $ = integral 1/2* ( 2*pi$0 ((x)dy - (y)dx) dt ) 1/2 (2*pi$0...

Homework Statement Given the power serie ##\sum_{n\ge 0} a_n z^n##, with radius of convergence ##R##, if there exists a complex number ##z_0## such that the the serie is semi-convergent at ##z_0##, show that ##R = |z_0|##. Homework EquationsThe Attempt at a Solution Firstly, since...

Homework Statement Calculate orbital radius of planet X using the given variables of its star: T=500 K, radius R=0.1 x Sun's radius, mass M=0.5 x Sun's mass and also its receives the same flux as the Earth receives from the Sun. I forgot to mention also that the orbit is circular, so the...

Homework Statement A lead nucleus contains 207 nucleons (82 protons and 125 neutrons) packed tightly against each other. A single nucleon (proton or neutron) has a radius of about 1 ✕ 10^−15 m. (a) Calculate the approximate radius of the lead nucleus. (b) Calculate the approximate radius of...

Homework Statement A spherical drop of water carrying a charge of 3×10^-19 has a potential of 500V at its surface (with V=0 at infinity) (a) What is the radius of the drop? If two such drops of the same charge and radius combined to form a single drop, what is the potential at the surface of...

Homework Statement A pipe of internal radius r1=0.03 m is built to have conductivity variable with radius: k=ar2, where a=250 Wm/K. 1) Find the critical radius r2 for the maximum heat transfer by convection from its external surface if the heat transfer coefficient is h2=30 W/m2K. Homework...

I have read that the Schwarzschild radius of a black hole with the mass-energy of the observable universe is roughly equal to the actual Hubble radius of 13.8 billion light years. And I have read that contrary to some popular esoteric interpretations such as "the universe is a black hole", "we...

It seems that the value has only 1 1/2 significant digits. Why are values for the measurement of this radius not more precise? What prevents a greater precision? I have recently been trying to learn about the sun's orbit in the Milky Way (MW) in order to calculate estimates re DM for another...

I recently came across a Wikipedia article about somebody's (?) law regarding limits on a moon's orbital radius because the sun's gravitational influence is greater than the planet's at some distance from the planet. As I recall, the law had two different names associated with it. In addition to...

Homework Statement The problem is to calculate the required thickness of the shell of a pressure vessel, given that the design pressure P is 400 psi, the strength S is 15800 psi, the corrosion allowance CA is 1/8"and ##R_{design}## is to be found by iteration. Homework Equations...

Homework Statement The center of a 1.00 km diameter spherical pocket of oil is 1.00 km beneath the Earth's surface. Estimate by what percentage g directly above the pocket of oil would differ from the expected value of g for a uniform Earth? Assume the density of oil is 8.0*10^2 (800) kg/m^3...

Hi There I am doing a little test program for some tire testing and just need to make sure I am doing something right, I am calculating the radius of gyration of my tire and wheel separately using the formulas from Dunlop...

Homework Statement This is for a practice question on an exam: I am able to finish the problem, if I could figure out how to find the radius of this arc the proton makes. Homework Equations I have nothing. The Attempt at a Solution I have tried arc length equations and just integrating the...

Homework Statement A star has an effective temperature T_{eff} and is observed to have a flux F. Show that the angular radius in arcseconds of the star (as seen from Earth) is given by \theta = (\frac{2.06 \times 10^5}{T_{eff}^2}) \sqrt{\frac{F}{\sigma}} Homework Equations L = 4 \pi R^2...

1. Compute the Larmor radius for a typical electron in the K corona.2. , , m=9.11×10-31 kg, q=1.602×10-19 CThe Attempt at a Solution My problem is I don't know where to find the other two values that correspond specifically to the the K corona. Then it becomes a simple plug-and-chug problem...

Homework Statement Given: y = sqrt(x), y=0, x=3 Find the volume of the solid bounded by these functions, revolved around B) y-axis and C) line x=3. (Disk method) Homework Equations Disk method of finding volume using π ∫ r2dy The Attempt at a Solution Ok so, the part of the problem that I...

Founding this : http://arxiv.org/abs/1502.05314 if I understood correctly the radius of the proton is smaller using muons instead of electrons. Could this be due to the fact that the gravitation force becomes repulsive at small distances so that the particles are kind of compressed by it ? I...

Homework Statement :[/B] Your car tire is rotating at 3.5 rev/s when suddenly you press down hard on the accelerator. After traveling 200 m, the tire’s rotation has increased to 6.0 rev/s. What was the tire’s angular acceleration? Give your answer in rad/s2. Homework Equations :[/B]...

Hi, I am new in this forum and still can find my way around easily. Please forgive me if I have posted this in a wrong section. I need help from seniors in the field of wireless transmission. I have done a bit of research but not enough to justify any conclusion. I have a project to setup a LRS...

Homework Statement Let ##\sum^{\infty}_{n=0} a_n(z-a)^n## be a real or complex power series and set ##\alpha = \limsup\limits_{n\rightarrow\infty} |a_n|^{\frac{1}{n}}##. If ##\alpha = \infty## then the convergence radius ##R=0##, else ##R## is given by ##R = \frac{1}{\alpha}##, where...

Homework Statement Separate variables and integrate to find an expression for r(t), given r0 at t=0 Homework Equations M=ρ(4/3)πr3, thus V=(4/3)πr3 dM/dt=Cr3 where C is a constant The Attempt at a Solution ∫dM=∫Cr3dt M+constant=?? I have no idea how to integrate r because it's a...

Question: Is there a way to calculate the radius of an electric field? By that I mean, say we have a cathode on one side, how far away can the anode be? Is there a way to calculate this? I'd imagine it would need to be experimentally derived due to the number of variables (shape of object...

Homework Statement A highway has an exit ramp that beings at the origin of a coordinate system and follows the curve ##y=\frac{1}{32}x^{\frac{5}{2}}## to the point (4,1). Then it take on a circular path whose curvature is that given bt the curve ##y=\frac{1}{32}x^{\frac{5}{2}}## at the point...

Homework Statement A truncated cone has smaller radius of 5 feet, larger radius of 10 feet, and a depth of 1 foot. Total volume is approximately 183 cubic feet. If I have water in there at x inches how much does the radius at the surface of the water increase per inch? Homework Equations f(x)...